The Clinical Core of the Emory Alzheimer's Disease Center (ADC) provides state-of-the-art diagnostic assessment of AD and other dementias, with a special emphasis on comorbid conditions that contribute to impaired cognition. The primary mission of the Core is to afford access to well-characterized patient pools with which to conduct innovative clinical and basic research projects. The Emory ADC has many unique features, including a large, ethnically diverse patient population and investigators with expertise in clinical and basic science related to a broad range of dementing illnesses. In addition, there is active involvement of established investigators with expertise in other conditions known to impair cognition in the aged population. An implicit component of the Clinical Core is the broadening notion of Mild Cognitive Impairment (MCI). A major challenge is to identify features that will predict which cases of MCI will progress to AD, or other dementing disorders, including dementia with Lewy bodies, vascular dementia, and Parkinson's disease. In addition, a substantial body of literature indicates that conditions, such as depression, cardiac disease, diabetes, hypertension, and sleep apnea, which are highly prevalent in the geriatric population, exert strong independent influences on cognitive function, and they can accelerate the progression of degenerative neurologic diseases. Through the activities of the Clinical Core and its interactions with other components of the Emory ADC, we will achieve three specific aims: 1) to evaluate cases of MCI, AD, and other dementias by systematic collection and evaluation of neurological and neuropsychological measures and examination of medical comorbidities;2) to enhance the care of patients and families through comprehensive clinical services, education, and access to promising clinical trials and other research activities;and 3) to support and promote research studies by sharing carefully and systematically collected data from registry participants, including clinical evaluations, family histories, DMA, and other biological materials.